Attach Debugger to Remote JVM using Debugger for Java Extension in VS Code when using Docker containers.

Dockerfile

# syntax=docker/dockerfile:1

FROM eclipse-temurin:17-jdk-jammy as base
WORKDIR /app
COPY .mvn/ .mvn
COPY mvnw pom.xml ./
RUN ./mvnw dependency:resolve
COPY src ./src

FROM base as development
# exposing 8000 in development enables attaching to remote jvm debugger
EXPOSE 8000
CMD ["./mvnw", "spring-boot:run", "-Dspring-boot.run.profiles=mysql", "-Dspring-boot.run.jvmArguments='-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:8000'"]


FROM base as build
RUN ./mvnw package

FROM eclipse-temurin:17-jre-jammy as production
EXPOSE 8080
COPY --from=build /app/target/spring-petclinic-*.jar /spring-petclinic.jar
CMD ["java", "-Djava.security.egd=file:/dev/./urandom", "-jar", "/spring-petclinic.jar"]

launch.json

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "java",
      "name": "Attach to Remote JVM",
      "projectName": "spring-petclinic",
      "request": "attach",
      "hostName": "localhost",
      "port": "8000", 
    },
  ]
}

• following Docker Java tutorial here: https://docs.docker.com/language/java/develop/
• when you get to the "Connect to Debugger" section, they provide instructions for IntelliJ but not for VS Code
• Under "Run and Debug", click dropdown near green play button and then select "Add Configuration"
• initially I had difficulty connecting VS Code Debugger for Java extension to remote jvm in Docker container.
• required exposing port 8000 in development, e.g. Dockerfile below "FROM base as development \ EXPOSE 8000"
• projectName was required for 'watch' feature of debugger and is root directory of project